mdmon: allow prepare_update to report failure.

[thirdparty/mdadm.git] / mdadm.h

diff --git a/mdadm.h b/mdadm.h
index 914d67cdec7c7661ebb66e3f826272768929c0c7..02a9288d86b8b1d334ad1aa0560afe7f64d5baba 100644 (file)
--- a/mdadm.h
+++ b/mdadm.h
@@ -929,7 +929,10 @@ extern struct superswitch {
        void (*sync_metadata)(struct supertype *st);
        void (*process_update)(struct supertype *st,
                               struct metadata_update *update);
-       void (*prepare_update)(struct supertype *st,
+       /* Prepare updates allocates extra memory that might be
+        * needed.  If the update cannot be understood,  return 0.
+        */
+       int (*prepare_update)(struct supertype *st,
                               struct metadata_update *update);
 
        /* activate_spare will check if the array is degraded and, if it